213 research outputs found
Observations on the mating behavior, spawn mass and larval development of Hydatina physis Linne, 1758 (Cephalaspidea: Hydatinidae) from Karachi
Reproduction of Hydatina physis was studied in a population from Karachi, Pakistan, including mating and egg laying behavior, spawn characteristics and development.Individuals first appear in the field in October and remain until March. The spawning occurs from mid-November till mid-February with a peak in December. During this period the individuals were also observed pairing. In captivity, mating lasts for 30 minutes, second mating occurs two days later. Oviposition occurs in a very interesting and unusual manner. The mother turns "up-side-down" with its food fully expanded and the shell completely hidden underneath, the expanded foot serves as protective cover to the eggs. Eggs are deposited in a complexly folded mass with a short stem and an adhesive disc. Capsules, arranged in a single layer, contain 4-6 eggs each of wich is 70 um in diameter. Development is planktotrophic and veligers hatch after 14 days at a temperature of 26-28 degrees Celsius
Observations on spawning and egg capsule of Melongena bucephala (Lamarck)(Mollusca: Gastropoda) from the Karachi coast
No work has been done on the reproduction of Melongena bucephala from northern Arabian Sea (Karachi coast). This paper presents a description of spawning, egg capsule and macromophology of eggs of M. bucephala collected from the rocky shore of Buleji on May 28, 1986 at a tidal height of 0.5m. The individual was found in the act of spawning. The egg mass and development of M. bucephala from Karachi coast are also compared with the Hemifusus ternatanus from the Pacific Ocean (Amio, 1963)
Studies on the filtration, feeding and excretion rates in Perna viridis, Marcia cor and Crassostrea gryphoides (Mollusca: Bivalvia) using P³² labelled Ankistrodesmes
The study deals with a series of experiments to investigate feeding and excretion in three species of bivalves: Perna viridis (Linné), Marcia cor (Sowerby) and Cassostrea gryphoides (Gould) from Manora Channel, Karachi. Bivalves were fed with suspensions of Ankistrodesmes labelled with P³². These animals showed a considerable variation in the average filtration rates depending upon species and the body lenght. Exceptionally high content of the P³² introduced with Akistrodesmes, got excreted as pseudofaeces and faeces within first three days following its absorption as a meal. The assimilated P³² is partly released as faecal material and its major proportion is directly transferred to the solution. As expexted the gonad and kidney are the main organs found responsible for excretion as comared to other body parts. Although, the assimilated P³² is mostly concentrated in the digestive glands, the results also show a significant presence of P³² in the gonads. Accumulation of P³² was the least in the foot
The determinants of earnings differentials in Ankara and İstanbul
In this study, an attempt is made to compare and contrast the determinants of
earnings differentials in Ankara and İstanbul. The determinants of earnings
differentials are first examined with semi-logarithmic single equation models based
on the basic human capital approach. Secondly, extended models are formed in
which all the variables are expressed as dummy variables. In general, the average
per hour earnings in İstanbul is higher than in Ankara. It is found that age, gender,
education, job status and marital status have significant effects on the explanatory
power of the model, whereas the impact of occupation is only modest.Publisher's Versio
Monetary Policy and Financial Asset Prices: Empirical Evidence From Pakistan
Monetary transmission mechanism assumed to be significantly influenced by the effect of policy decisions on financial markets. However, various previous studies have come up with different outcomes. The purpose of this study is to examine the impact of monetary policy on different asset classes (shares and bonds) in Pakistan. This study using stock price and bond yield as dependent variable and discount rate, money supply, inflation, and exchange rate are independent variables. Data of all variables have collected from 2010 to 2016, and Vector Autoregressive (VAR) technique has applied. The empirical results indicate that there is an impact of monetary policy components on both stock and bond market as an increase in policy rate causes decline in stocks prices and bonds yields. The findings of this study will help the potential investors in making long-term (in general) and short-term (in particular) investment strategies concerning monetary policy.DOI: 10.15408/sjie.v7i2.709
Trade-off curves applications to support set-based design of a surface jet pump
Knowledge has become the most important asset of companies, especially in improving their product development processes. The set-based design approach is an efficient way of designing high quality, optimised designs. However, it requires a proven knowledge environment. Trade-off curves (ToCs) have the capability of providing the right knowledge and displaying it in a visual form. Although there are a few applications of ToCs that have recently been published in the literature, none of them demonstrates an integrated implementation of ToCs throughout the SBCE process. This paper presents the integrated use of ToCs, based on both physics-knowledge and proven knowledge, in order to compare and narrow down the design-set and to achieve an optimal design solution. These are key activities of the SBCE process model. Since an accurate, documented and visual knowledge environment is created by the use of ToCs within SBCE, the integrated approach proposed in this paper plays a vital role in eliminating the need for prototyping and testing at the early stages of product development. The integrated approach was implemented in an industrial case study for a surface jet pump. Surface jet pumps are used to increase the production rate of low-pressure oil/gas wells. It has been found that through ToCs, the conflicting relationships between the characteristics of the product can be understood and communicated effectively among the designers. This facilitated the decision-making on an optimal design solution in a remarkably short period of time. Furthermore, the surface jet pump resulting from the case study achieved an increase of the oil/gas production by nearly 60%
Evaluation of e148q and concomitant aa amyloidosis in patients with familial mediterranean fever
The aim of the study was to compare the clinical phenotype of patients with familial Mediterranean fever (FMF)-related AA amyloidosis, according to the age of FMF diagnosis and E148Q genotype. Patients with biopsy-confirmed FMF-related AA amyloidosis were included in the study. Tel-Hashomer criteria were applied in the diagnosis of FMF. All patients had detailed baseline assessment of clinical features, renal functions, genetic testing, histopathological diagnosis of amyloidosis, and treatment received. Multiple comparisons were performed according to the age of diagnosis, disease phenotype, mutation, and mortality. Our study included 169 patients with a diagnosis of AA amyloidosis. There were 101 patients diagnosed with FMF \u3c 18 years of age and 68 patients diagnosed who were ≥18 years of age. The three most common clinical manifestations were fever (84.6%), abdominal pain (71.6%), and arthritis (66.9%). The most common allele among FMF patients was M694V (60.6%), followed by E148Q (21.4%), and M680I (10.3%). The most frequent genotypes were M694V/M694V (45.0%), M694V/E148Q (14.8%), and E148Q/E148Q (11.2%) among 169 patients in our cohort. During the follow-up period, 15 patients (10 male, 5 female) died, of whom 14 had M694V homozygous genotype and one was homozygous for E148Q. Clinicians should be aware of patients with homozygous E148Q genotype for close monitoring and further evaluation. The possible relationship between E148Q and AA amyloidosis needs to be confirmed in other ethnicities
A synchrotron radiation X-ray scattering study of aqueous solutions of native DNA
Synchrotron radiation small-angle X-ray scattering (SAXS) was used to investigate solutions of native DNA at different ionic strengths and temperatures. The mass per unit length, radius of gyration of the cross-section of DNA and apparent second virial coefficient (A2) were obtained from Zimm plots in the rodlike particle approximation. The values of A2 obtained in this way are positive and almost constant indicating that the repulsive interactions still influence the scattering patterns at resolutions as high as 5-8 nm. SAXS measurements in continuous temperature scans indicate that the rod approximation is valid over a wide temperature range during DNA melting and confirm that the rodlike-wormlike transition temperature increases with ionic strength
The set-based concurrent engineering application: a process of identifying the potential benefits in the surface jet pump case study
The Set-Based Concurrent Engineering (SBCE) is the methodology that can improve the efficiencies and effectiveness of product development. It is found that the SBCE approach provided a suitable knowledge environment to support decision making throughout the development process. This paper presents the potential tangible benefits gained from the application of the SBCE in an industrial case study of a Surface Jet Pump (SJP) that is used to revive the production of oil/gas from the dead wells. The well-structured SBCE process model and the process of identifying the potential benefits proposed in this paper will clarify the gap in the development of the SBCE in the company. The potential tangible benefits are established in a few key areas such as product innovation, product performance, manufacturing cost, and project success rate
Relevant boundary perturbations of CFT: A case study
We consider simple CFT models which contain massless bosons, or massless
fermions or a supersymmetric combination of the two, on the strip. We study the
deformations of these models by relevant boundary operators. In particular, we
work out the details for a boundary operator with a quadratic dependence on the
fields and argue that some of our results can be extended to a more general
situation. In the fermionic models, several subtleties arise due to the
doubling of zero modes at the UV fixed point and a ``GSO projected'' RG flow.
We attempt to resolve these issues and to discuss how bulk symmetries are
realised along the flow. We end with some speculations on possible string
theory applications of these results.Comment: 16 pages, late
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